1. Field
The present invention relates to a method for estimating a power of a fuel cell that estimates in real time an available power of the fuel cell to determine whether a cold start can be completed while the temperature of the fuel cell is being raised for the cold start.
2. Description of the Related Art
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
When water inside a fuel cell freezes due to low temperature, a temperature-raising process is required to secure power of the fuel cell.
FIG. 1 is a graph illustrating a variation in a performance output of a fuel cell while the temperature of the fuel cell is raised according to a conventional art. Referring to FIG. 1, at the beginning of the temperature-raising process, the fuel cell stack in a low temperature state outputs the performance represented as the points on line {circle around (1)}. While the temperature-raising process is in progress, the stack voltage gradually increases at a nearly constant current as in line {circle around (2)}. Then, when the temperature-raising process is completed, the performance is represented as the points on line {circle around (3)}. In other words, as the fuel cell having the stack performance represented as line {circle around (1)} cannot output a power required to drive a vehicle, the temperature-raising process progresses until the fuel cell has the stack performance represented as line {circle around (3)}.
However, the power of the fuel cell during the temperature-raising process is low compared to the power required to drive a vehicle. That is because the performance of the stack decreases below the voltage conditions necessary for normal operation of high-voltage components when a current for driving the vehicle is applied.
In other words, it is unnecessary to continue the temperature-raising operation until the power of the fuel cell reaches the power required to drive the vehicle. However, as the technique for ascertaining the degree of temperature-increase or an available power of the fuel cell during the temperature-raising operation is insufficient, starting of the ignition may be excessively delayed until the temperature is sufficiently raised.
The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art.